Power supplies designed for providing an operating voltage to an electronic device typically utilize a voltage regulator to provide a substantially constant voltage to a load device despite variations in the current dissipated by the load. Voltage regulators can include a current sensor to sense the current provided to the load. The sensed current can be used by a feedback portion of the voltage regulator to protect the load device and the power supply from an over-current situation resulting from a short circuit fault or other failure. The sensed current can also be used by a feedback system whereby the voltage provided to the device is controlled, independent of the current provided to the device.
A typical current sensing technique includes monitoring a voltage drop across a sense resistor which is inserted in series with an output terminal of the voltage regulator, and thus is in the current path of the load device receiving power from the regulator. However, this current sensing technique can be undesirable due to the power consumption caused by the sense resistor.